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Comment by cperciva | Hacker News Reader

Question for people with more aviation knowledge than me: Don't games like this make life hard for air traffic controllers? 35000' is right in the middle of normal airspace; isn't it much easier if planes are flying along standard routes between airports?

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Altitude is determined by direction in alternating chunks of 1000ft. So, say, southbound traffic flies at 29000, then 30000 is westbound, 31k north, 32k east, and then 33 is southbound again.

So at cruising altitudes every airspace can accommodate travel in any direction... the controllers along the way probably didn't even realize that anything out of the ordinary was happening except for talking to a Boeing callsign (as opposed to the call sign of one of the major airlines that typically operate flights at this altitude, Boeing operates its own "airline" in the regulatory sense just for test flights).

Given the length of that route (and all those arbitrary GPS waypoints!) I'd think ATC would catch on pretty quickly.

ATCs along the way don't necessarily need to get the full picture. Each one is responsible for a zone. They have planes about to enter their zone, they route them/land them and then the plane moves out. Not saying they can't easily get the flight plan and figure it out, but they probably wouldn't normally do it.

But no matter how small the zone is, the point where the plane is to make a 90/180/270 degree turn is only in one zone. That means the ATC responsible for that zone would see it. Are normal planes really doing 90 degree turns?

I haven't looked at the route that Flightaware provides yet, but there are a LOT of defined navigational fixes and standard routes between these fixes. Its possible the crew simply assembled a series of fixes (and standard routes) to get the desired shape.

Enroute charts tend to look a lot more like a US highway map than an Interstate system map.

This flight got up to 42,000 feet if you look at the elevation graph. I didn't know planes flew that high.

> I didn't know planes flew that high.

Well, it is a test flight of a brand-new plane. Also, some "planes" can go as high as they want in the atmosphere, even up to space (kinda).

I don't know what you mean by "planes." All airfoil based aircraft have a limitation on how high they can fly before the air gets too thin for their wings to generate sufficient lift (known as their "operating ceiling").

The only exception to this I know of would be a craft with enough thrust to use power as the source of lift (like the space shuttle).

My flights between Taiwan and California in the last ~18 months were usually around 40,000 feet give or take a bit in 747s and 777s.

That's high for a large body airliner, but some smaller business jets can go higher because they have better aerodynamics and engines. Service ceiling figures from wikipedia:

  Gulfstream 550 and Dassault Falcon 7x: 51k

  F14, F18, B52, and B-2: 50k
  F15, F16, F35, B-1B, Su-47: 60k
  F22, Typhoon, and PAK FA: 65k
  U-2: 70k
  SR71: 85k

  A380, A350: 43k
  A340, A330: 41k
  A320: 39k

  Boeing 787, 777: 43k
  Boeing 757, 727: 42k
  Boeing 747-400: 41k
  Boeing 737: 35k

The 85k for the SR-71 is the unclassified information that has been made available. Rumor has it they hit 100k+ with the SR-71. Figures on actual ceiling for the SR-71 flights that were made have never been made public.

<http://www.messybeast.com/dragonqueen/cockpit-chatter.htm...; (Flight level is x10000, so FL600 is 60,000 feet)

SR-71 Blackbird was crossing the control-zone of London Control. Evidently the controller didn't know the service ceiling of this aircraft is around 30,000 metres (yes metres, not feet!). There are so many variations on this item that the original event has evidently become part of aviation folklore or joke-lore.

Pilot: "Radar, Good Day, Airforce Blackbird, request FL 600(!)"

Controller (amused): "Sir, if you can reach, you are cleared FL 600"

Pilot: "US Air Force Blackbird, leaving FL 800, descending Level 600..."

So many good stories about that bird.

One of my favorites:

https://groups.google.com/forum/?fromgroups#!topic/rec.aviat...

"There were a lot of things we couldn't do in an SR-71, but we were the fastest guys on the block and loved reminding our fellow aviators of this fact. People often asked us if, because of this fact, it was fun to fly the jet. Fun would not be the first word I would use to describe flying this plane. Intense, maybe. Even cerebral. But there was one day in our Sled experience when we would have to say that it was pure fun to be the fastest guys out there, at least for a moment. ..."

The entire path is communicated to ATC in advance when the flight plan is filed, so they can foresee the route on screen when directing other traffic. Also, much of the flight was in the evening and late night, so traffic controlling load would have been lower for them.

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